TAMPA, Fla. (AP) -- Republicans have strengthened the pro-gun-rights portion of their party platform, including a new call for unlimited bullet capacities in guns, in a defiant response to criticism that followed recent mass shootings at a Colorado cinema and an Arizona congresswoman's gathering.

The 2012 platform, approved this week by GOP convention-goers who nominated Mitt Romney for president, also endorses "stand your ground" rights for gun owners. That legal concept, which says gun bearers don't have to retreat if they feel threatened in a public place, drew national attention after February's fatal shooting of an unarmed Florida teenager by a neighborhood watch volunteer.

Republicans traditionally embrace gun rights in their quadrennial party platforms. The one approved this week went farther than those of 2004 and 2008.

Gun control advocates see it as an audacious answer to calls for firearms restrictions after a gunman killed 12 people in Colorado last month, and another gunman killed six people in Tucson, Ariz., early last year. Gabrielle Giffords, then a Democratic congresswoman holding an outdoor meeting, was gravely wounded in the Tucson assault.

"Gun control only affects and penalizes law-abiding citizens," the 2008 Republican platform said. This year's platform adds: "We oppose legislation that is intended to restrict our Second Amendment rights by limiting the capacity of clips or magazines."

The shooters in Colorado and Arizona used large-capacity weapons capable of firing many rounds quickly.

The 2004 GOP platform said "law-abiding citizens" should have the right "to own firearms in their homes for self-defense." This year's platform supports "the fundamental right to self-defense wherever a law-abiding citizen has a legal right to be."

It calls for federal laws "that would expand the exercise of that right by allowing those with state-issued carry permits to carry firearms in any state that issues such permits to its own residents."

Dan Gross, president of the Brady Campaign to Prevent Gun Violence, said that, by making these changes, Republican leaders have "put themselves farther out of touch with their constituents."

His group supports bans on large-capacity weapons, which it says are "designed to shoot a lot of people quickly and efficiently."

David Keene, president of the National Rifle Association, told the NRA News that the 2008 GOP platform "was perhaps the most gun-friendly platform that any party had ever adopted," and "this year's Republican platform is even stronger in terms of dedicating a major party to the protection of the Second Amendment."

Presidential nominees, not to mention the general public, often ignore party platforms. Top Republicans in Tampa, however, implored the public to study the 50-page platform document.

"We invite Americans to consider this platform, a call for dramatic change in government," Virginia Gov. Bob McDonnell said in his convention speech Tuesday.